The Carbon Dioxide Sweet Spot

When we think of breathing we automatically think of oxygen. We know that oxygen is the fuel that muscles need to work efficiently and breathing how we take in this life-saving gas. Indeed we often consciously take a deep breath to ‘fill up with oxygen’ for energy or vitality. The truth is however that we are rarely short of oxygen. Our blood is almost always already fully saturated with oxygen. So what makes us think that we need to breathe deeply to fill up with air.

As odd as this may seem, it’s not the level of oxygen that stimulates us to breathe, but the level of carbon dioxide or CO2 in our blood. Receptors in the brain are continually monitoring our levels of carbon dioxide and the acidity or pH level of the body along with the levels of oxygen. Under normal circumstances these receptors are continually adjusting our breath to keep these levels in balance.

However most of us have bad breathing habits that interfere with this natural process. We either over-breathe or under breathe. By far the most common is over-breathing (and most of us don’t even realise it!). Over breathing has the effect of releasing or ‘blowing out’ too much carbon dioxide, which leaves us depleted of the gas. Under breathing is much less common where there is an over-supply of carbon dioxide in the blood. (Despite what you might think, breath holding doesn’t lead to under breathing)

Carbon dioxide performs a number of vital functions in the human body, including:

Delivers O2 to the Cells

The function of haemoglobin in the blood is to deliver oxygen to the cells. However it is CO2 that tells haemoglobin to release oxygen to the tissues. If you have a low level of CO2, haemoglobin will not release its oxygen and your cells and tissues, including the brain, will suffer from a lack of vital oxygen.


Helps Regulate the Acidity Level or pH Level of the Blood

CO2 is converted into carbonic acid carried in the body as carbonic acid. If we lose it (breathe too much out), we have relatively less acid and the body’s pH rises and becomes more alkaline. Maintaining the correct pH balance is crucial for the health of practically all the organs in the body, including the digestive system, the immune system, the endocrine system.

Keeps Blood Vessels and Airways Open

CO2 is also a very powerful dilator, or relaxer, of blood vessels and airways. If you have low CO2 your body will respond by constricting these vessels. This will affect blood flow to the brain and heart, and air flow in and out of the lungs. This can lead to high blood pressure, pressure on the heart and the respiratory systems. Adequate CO2 helps to keep the blood vessels and airways open and healthy.

Calms the Nervous System.

The sympathetic nervous system controls the fight or flight response in the body which is the part activated by stress. Lack of CO2 can be both the causes the effect of triggering the sympathetic nervous system

Raising the level of CO2 in the blood has the effect of activating the para-sympathetic nervous system – the one that calms us down. (It how breathing into a paper bag works for someone having a panic attack. By breathing back in air high in CO2 it restores the level of CO2 in the blood which in turn stimulates the para-sympathetic nervous system to bring calm.) Maintaining good levels of CO2 helps with anxiety, stress and sleep.

In short, our levels of CO2 affect almost every system in the body and our breath plays a crucial role in keeping our physiological systems in balance. If our breathing is free and spontaneous this balancing function is happening naturally all the time. If however we have developed breathing patterns like shallow breathing or over breathing, then we interrupt this natural process.

The most effective way to change these patterns is through the practice of new habits. Start by bringing your breath right down into your belly through the practice of diaphragmatic breathing. Abdominal or diaphragmatic breathing is known to keep the levels of CO2 correct, and is also great to reduce stress, help sleep and lower blood pressure.

At any moment in time during the day pay attention to how you are breathing. Just giving your breath your attention alone seems to stimulate a deeper, slower, calmer breath. A daily practice helps to maintain the effects in the long term. Spend 5 minutes in the morning to set you off for the day and 5 minutes in the evening to help you relax and prepare for sleep.  Our breath is free, quick and available at any moment. It is the best tool available to help you stay well, healthy and full of energy.